1. Field of the Invention
The present disclosure generally relates to a lubricant application apparatus including a blade for smoothing lubricant supplied on a surface of an image carrying member, and an image forming apparatus, such as a copier, a facsimile, or a printer, and a process cartridge using such a lubricant application apparatus.
2. Discussion of the Background Art
Typically, an image forming apparatus using electrophotography includes a cleaning unit that cleans a surface of an image carrying member after transferring an image from the image carrying member to a transfer member (e.g. a sheet). For example, after an image transfer process, toner may remain on the surface of the image carrying member, and such remaining toner needs to be removed to prepare the image carrying member for another image forming process. Such a cleaning unit may typically use a cleaning blade made of an elastic member (e.g., polyurethane rubber) because such a blade may have a simple configuration and also a good level of a cleaning function for removing toner or the like.
Further, an image forming apparatus includes a lubricant supply unit, which supplies lubricant (e.g., aliphatic acid metal salt) to a surface of the image carrying member to reduce the friction coefficient between a cleaning blade and an image carrying member. If an amount of lubricant supplied to the surface of the image carrying member is not sufficient (e.g., lubricant amount is too little), such a friction coefficient may not be reduced sufficiently, and thereby some drawbacks may occur due to a high friction coefficient. For example, curling of the cleaning blade and a shorter lifetime of the image carrying member may result.
On the other hand, if an amount of lubricant supplied to the surface of the image carrying member is excessive (e.g., lubricant amount is too great), some lubricant may adhere to devices or the like disposed around an image carrying member, and thereby some drawbacks may occur due to such lubricant adhesion. For example, an abnormal image may result due to lubricant adhesion to a charging device or a development agent carrier.
Accordingly, in such an image forming apparatus including a function of supplying lubricant on to an image carrying member, a lubricant supply amount onto the image carrying member may need to be controlled to a given level.
Japanese Patent Application Publication 2000-330443 (hereinafter background art 1) and Japanese Patent Application Publication 2001-305907 (hereinafter background art 2) disclose image forming apparatuses including a cleaning blade and a lubricant supply unit including a lubricant smoothing device. In such configurations, the lubricant supply unit is positioned at a downstream side of a surface movement direction of an image carrying member with respect to a contact point of the cleaning blade and the image carrying member, and thereby the lubricant smoothing device is positioned at a downstream side of a surface movement direction of an image carrying member with respect to the cleaning blade. In such an image forming apparatus, the surface of the image carrying member is cleaned well before lubricant is supplied on to the image carrying member, and thereby lubricant supplied onto the surface of the image carrying member can be uniformly smoothed by the lubricant smoothing device. Further, such configurations can prevent a phenomenon that lubricant adheres to remaining toner, which remains on the image carrying member after a toner image transfer.
If such configurations are not employed, remaining toner may come to the lubricant smoothing device with lubricant applied onto the image carrying member, and the lubricant smoothing device may remove some lubricant with remaining toner, which is not preferable. Such an undesirable cleaning phenomenon of lubricant can be prevented if the above-described configuration is employed. Accordingly, such a configuration may be effective to control a lubricant supplying amount or consumption amount.
Background arts 1 and 2 each disclose a lubricant smoothing device of blade type, but the lubricant smoothing devices are supported in different manners. In background art 1, the lubricant smoothing blade is supported by a counter-direction configuration. Specifically, a support device supports the lubricant smoothing blade from a downstream side of the surface movement direction of the image carrying member with respect to a contact area of the lubricant smoothing blade and a surface of an image carrying member. On the other hand, in background art 2, the lubricant smoothing blade is supported by a trailing-direction configuration. Specifically, a support device supports the lubricant smoothing blade from an upstream side of the surface movement direction of the image carrying member with respect to a contact area of the lubricant smoothing blade and a surface of an image carrying member.
The lubricant smoothing blade can be contacted to the image carrying member with a higher contact pressure in the counter-direction configuration compared to the trailing-direction configuration. Accordingly, a phenomenon of lubricant passing through at a contact point of the lubricant smoothing blade can be prevented more effectively by employing the counter-direction configuration compared to the trailing-direction configuration.
However, the lubricant smoothing device contacting the image carrying member moving in a given direction (e.g., rotating) may vibrate due to a friction with the image carrying member even if the counter-direction configuration is employed.
If the lubricant smoothing blade contacts the image carrying member with a small contact area, the lubricant smoothing blade may not stably contact the contact point with the image carrying member due to such a vibration. Under such a vibrated condition, the lubricant smoothing device may not function properly, and thereby some lubricant, which comes to the contact point of the lubricant smoothing blade, may not be screened by the lubricant smoothing blade. In other words, lubricant may pass through the lubricant smoothing device without an adequate control of a lubricant amount. If such a passing occurs, an amount of lubricant supplied to the image carrying member cannot be controlled properly, and thereby a resultantly produced image may have a lower image quality.